Disc drives are common data storage devices. A typical disc drive includes a rigid housing or deck that encloses a variety of disc drive components. The components include one or more discs having data surfaces that are coated with a magnetizable medium for storage of digital information in a plurality of circular, concentric data tracks. The discs are mounted on a spindle motor that causes the discs to spin and the data surfaces of the discs to pass under respective hydrodynamic or aerodynamic bearing disc head sliders. The sliders carry transducers, which write information to and read information from the data surfaces of the discs.
An actuator mechanism moves the sliders from track-to-track across the data surfaces of the discs. The actuator mechanism includes a motor, such as a voice coil motor, that is generally disassociated from the discs in terms of its relative position within the disc drive housing. Under the control of electronic circuitry, the motor is operated so as to move the actuator mechanism from track-to-track across the data surface of a disc.
The slider typically includes a bearing surface, which faces the data surface of a disc. As the disc rotates, the disc drags air under the slider and along the bearing surface in a direction approximately parallel to the tangential velocity of the disc. As the air passes beneath the bearing surface, air compresses along the airflow path and causes the air pressure between the disc and the bearing surface to increase. This increase in air pressure creates a hydrodynamic or aerodynamic lifting force that counteracts the load force and causes the slider to lift and fly above or in close proximity to the data surface of the disc.
To increase recording area density, it has become desirable, under certain circumstances, to manufacture the disc as smooth as possible in the data zone to accommodate a lowered fly height. During disc drive operation, serious damage to the disc and a loss of data would result during lowered fly height if a particle were to become present between the disc and the recording head. Currently, disc drives contain filtration systems to protect the disc from these particles. A filtration system generally contains sub-systems such as a breather filter, a re-circulation filter, a carbon adsorber and diffusion path.
The breather filter is responsible for removing contaminants from incoming air entering from the external environment into the disc drive. To ensure that air flows through the breather filter, the location for the breather filter is typically in a low pressure region. Generally, breather filters are placed under or above the disc where a negative air pressure region exists with respect to an ambient air pressure outside of the disc drive. However, airflow through the breather filter is not always completely clean. The airflow may contain unfiltered particles or chemical vapor. As a result, the placement of the breather filter under or above the disc exposes the disc to a great risk of becoming contaminated by harmful materials. Furthermore, particles that are trapped by the breather filter can be deposited onto the disc under a shock or vibration event.
Embodiments of the present invention provide solutions to these and other problems and offer other advantages over the prior art.